Qualification of a surface plasmon resonance assay to determine binding of IgG-type antibodies to complement component C1q.

Interaction of therapeutic antibodies with complement component C1q are frequently part of pharmaceutical characterization and production process comparability studies. Assays currently used to assess this interaction and/or the activation of the complement cascade are often cumbersome, time consuming or imprecise. We here report the further development, successful qualification and suitability evaluation of an SPR-based C1q binding assay for the characterization of IgG-C1q interactions. We evaluate different IgG subtypes and well-described mutants of IgG1. The assay offers a suitable alternative for extended characterization of interactions of IgG1 and IgG3 with complement component C1q.